Right. Been working this out in my scrabble brain...

Cero
Cod
Code
Codder
Coed
Cor
Cord
Corded
Doc
Doe
Dor
Deco
Doer
Dore
Odd
Ode
Orc
Ore
Odder
Rec
Red
Redo
Roc
Rod
Rode
Roe



If there is more than this, id otn know them